Tomographic Evaluation of Bone Height Between the Mandibular Canal and the Inferior Cortex of the Mandible Related to Bicortical Screws Fixation

Abstract

Study Design: Original Article. Objective: The surgical treatment of mandibular fractures has undergone several changes over the past 100 years, since the use of wires and intermaxillary fixation, until today where most of the fractures are treated with internal fixation using plates and screws. For the correct use of this hardware, the surgeon must have adequate knowledge of jaw anatomy to prevent complications during the insertion of screws like in fractures of the mandibular body and angle, when the screws of the plate installed in the compression zone can damage the inferior alveolar nerve within the mandibular canal. Methods: To minimize this complication, 66 hemimandibles of adult patients were analyzed in CT scans and manipulated with Dental Slice® software, (BioParts®, Brazil) and measured the shortest distance from the inferior cortex of the mandibular canal to the inferior cortex of the mandibular body during the path of the inferior alveolar nerve, since the mandibular foramen until the mental foramen. Results: The result obtained showed a wide variation of the shortest distance measured (3.52 mm–11.5 mm) with an average of 7.99 mm. Conclusion: The conclusion demonstrated a minimum distance of 3.52 mm below the cortical mandibular canal to the lower border of the mandible and should be considered as a safety margin during the application of fixing the material in the region of the mandibular body.